A natural trigger that enables stem cells to become any cell-type in the body has been discovered by scientists. A natural trigger that enables stem cells to become any cell-type in the body has been discovered by scientists. Their discovery could help scientists improve techniques enabling them to turn stem cells into other cell types in the laboratory. These could then be used to test drugs or help create therapies for degenerative conditions such as Parkinson's disease, motor neuron disease, multiple sclerosis and liver disease.